Rounds/catches with LilyPond

[Ben Rudiak-Gould]

Hello lilypond-users.

I'd like to engrave rounds with LilyPond 2.13 in a part-parallel
format similar to this:

  http://www.archive.org/stream/nationalsongbook00stan#page/n255/mode/2up

Although this looks simple compared to a lot of the crazy stuff in the
snippet repository, there is a problem that I don't know how to solve:
sometimes ties, slurs, or word hyphens/extenders have to stretch from
the end of one staff to the beginning of the next, as though the
staves were sequential instead of parallel. (See "She Weepeth Sore",
above, for an example). Logically they are sequential, of course, but
I have to tell LilyPond they're parallel to make the notes line up.

Is there any way to solve this? I don't want to turn on strict note
spacing since it would uglify the score. The best idea I've had is to
render three consecutive copies of the piece (with the parts rotating)
and then somehow drop the first and third copies late in the rendering
process. But that would introduce a bunch of gunk into the source file
that's unrelated to the logical structure of the piece, it would
generate spurious warnings for ties and dashes at the end of the third
copy, LilyPond wouldn't know that the last system is really the last
so ragged-last options probably wouldn't work, etc. Is there a more
elegant solution?

Thanks,

-- Ben